China has released statistics on the income gap between rich and poor after keeping the figures secret since 2000.

Ma Jiantang, chief of the National Bureau of Statistics, told a news conference Friday that figures from 2003 to the present showed “the income gap was rather big.”

The NBS used the “Gini coefficient” – a standard measure of economic inequality to measure the gap. The index ranges from 0 – perfect equality, to 1 – total inequality. Jiantang told reporters that China's coefficient stood at 0.474 last year, placing the country among some of the world's most unequal societies.

China's economic boom has made billionaires out of some entrepreneurs, and Communist Party officials seem to live in luxury. However, the majority of China's people have experienced little growth in income.

Narrowing the economic gap is one of the most pressing issues issues facing the government, which fears that civil unrest could topple the ruling party.